1. Field of the Invention
The present invention relates generally to the crushing, grinding, comminuting or similarly processing materials such as mineral ores, rock and other materials, and more particularly to apparatus for use in such processing. In one example application sulphurated minerals are processed to produce particulated matter of a size between 100 and 20 microns.
2. Description of Related Art
Grinding mills are one form of apparatus used for processing materials as described above. Typical grinding mills generally comprise a drum shaped shell mounted for rotation about its central axis. The axis of the shell is generally horizontally disposed or slightly inclined towards one end. The interior of the shell forms a treatment chamber into which the material to be processed is fed. In one form of mill known as a SAG (semi autogenous grinder) a grinding medium such as balls or rods is fed to the treatment chamber with the material to be processed. During rotation of the shell the grinding medium acts on the material to cause the crushing or grinding action. In conventional mills and SAG mills the aspect ratio of the mill diameter to the mill length is ≦1 and >1 respectively. The grinding medium and material to be processed are carried up the side of the shell as a result of the centrifugal force created by rotation of the shell whereafter it falls towards the bottom of the shell under the influence of gravity. To assist in lifting the material up the side of the shell, lifter bars are often provided which are secured to the interior surface of the shell. The lifter bars extend generally longitudinally of the shell and are circumferentially spaced apart around the inner surface. The higher the material travels up the shell the better the grinding of the material. Examples of such mils are described in Chilean Patents 39450 and 36411.
FIG. 1 is a partial schematic illustration of a typical grinding mill having a shell 10 with a plurality of lifter bars 12 mounted to the inner surface of the shell 10. The lifter bars 12 are circumferentially spaced apart around the inner surface of the shell 10 and extend in the direction of the axis of rotation of the shell. The spaces between adjacent lifter bars 12 form channels 14 of width J. The length of the bars 12 is shown as LM which is the inner length of the shell in the direction of rotation thereof. Preferably the number of channels 14 is the same as the number of lifter bars 12.
FIGS. 2 to 4 are various illustrations of conventional liner assemblies adapted to be installed in a mill as shown in FIG. 1.
As shown in FIG. 2, each channel 14 is adapted to have mounted therein a liner assembly 20. The conventional liner assembly 20 includes a metal base member 22 which is adapted to be mounted to the inner surface of the shell by suitable fastenings such as bolts (not shown). The base member 22 includes an elongated plate having mounting elements 23 thereon. The liner assembly further includes a generally flat wear element 24 which is mounted to the base member 22. The wear element 24 may be formed of an elastomeric material or metal for providing protection against abrasion and impact. Because of the constant impact forces applied to the wear elements when the mill is in operation, they will tend to break after a period of time. When breakage occurs the mill needs to be stopped while they are replaced. This can be time consuming and reduce the overall productivity of the mill.
It is an object of the present invention to provide an improved mill liner assembly which alleviates the aforementioned problem.